The Cisco Unified IP Phone 6921 supports two lines and offers a full-duplex speakerphone for a more productive, more flexible, and easier-to-use endpoint experience. The Cisco Unified IP Phone 6921 supports single-call per-line appearance, offering traditional telephony-like user experience for customers who seek this type of call interaction for their users. Fixed keys for hold, transfer, and conference; tri-color LED line and feature keys also make the phone simpler and easier to use.

The Cisco Unified IP Phone 6921 is also more energy-efficient and eco-friendly, in support of customer green initiatives. A Deep-Sleep option provides energy savings. With this option, the Cisco Unified IP Phone 6921 consumes up to 50 percent less power in off-hours versus when the phone is idle during normal business hours. In addition, reground and recyclable plastics deliver a more earth-responsible solution.